improved sql parser export parameter sharding support.

src/test/java/com/alibaba/druid/bvt/sql/ExportParameterShardingTest.java

@@ -0,0 +1,63 @@
+package com.alibaba.druid.bvt.sql;
+
+import com.alibaba.druid.sql.SQLUtils;
+import com.alibaba.druid.sql.ast.SQLStatement;
+import com.alibaba.druid.sql.visitor.SQLASTOutputVisitor;
+import com.alibaba.druid.util.JdbcConstants;
+import com.alibaba.fastjson.JSON;
+import junit.framework.TestCase;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Created by wenshao on 23/11/2016.
+ */
+public class ExportParameterShardingTest extends TestCase {
+    String dbType = JdbcConstants.MYSQL;
+
+    public void test_exportParameter() throws Exception {
+        String sql = "select * from t_user_0000 where oid = 1001";
+
+        List<SQLStatement> stmtList = SQLUtils.parseStatements(sql, dbType);
+
+        assertEquals(1, stmtList.size());
+
+        SQLStatement stmt = stmtList.get(0);
+
+        StringBuilder out = new StringBuilder();
+        List<Object> parameters = new ArrayList<Object>();
+        SQLASTOutputVisitor visitor = SQLUtils.createOutputVisitor(out, dbType);
+        visitor.setParameterized(true);
+        visitor.setParameterizedMergeInList(true);
+        visitor.setParameters(parameters);
+
+        stmt.accept(visitor);
+
+        System.out.println(out);
+        System.out.println(JSON.toJSONString(parameters));
+
+        String restoredSql = restore(out.toString(), parameters);
+        assertEquals("SELECT *\n" +
+                "FROM t_user_0000\n" +
+                "WHERE oid = 1001", restoredSql);
+    }
+
+    public String restore(String sql, List<Object> parameters) {
+        List<SQLStatement> stmtList = SQLUtils.parseStatements(sql, dbType);
+
+        assertEquals(1, stmtList.size());
+
+        SQLStatement stmt = stmtList.get(0);
+
+        StringBuilder out = new StringBuilder();
+        SQLASTOutputVisitor visitor = SQLUtils.createOutputVisitor(out, dbType);
+        visitor.setParameters(parameters);
+
+        visitor.addTableMapping("t_user", "t_user_0000");
+
+        stmt.accept(visitor);
+
+        return out.toString();
+    }
+}